Using this D2 Racing RS Coilover Kit is easy. First, make sure your vehicle is the right model (2002 - 2007 Subaru WRX, 2004 STI, or 2003 - 2007 Forester). You can adjust the height and preload according to your driving needs. The 36 - way dampener and rebound adjustments let you fine - tune the performance. When installing, be careful with the pillowball upper or top mounts. These are made of special 6061 powder - coated aluminum, so handle them gently. For maintenance, check the Teflon - coated threads regularly to make sure there's no rust. If you notice any issues, this kit is rebuildable and can be serviced in the US, so don't hesitate to get it fixed.